Method of fabricating a reaction chamber for a fuel storage assembly

ABSTRACT

A method for manufacturing a reaction chamber comprising a fuel insert and an elastic enclosure with a body and an opening, the method including the steps of stretching the body of the elastic enclosure to define a working lumen, orienting the metal hydride insert within the working lumen, and restituting the elastic enclosure over the insert.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/400,412, filed 26 Jul. 2010, which is incorporated in its entirety bythis reference.

TECHNICAL FIELD

This invention relates generally to the reaction chamber field, and morespecifically to a new and useful method of manufacturing a reactionchamber in the reaction chamber field.

BACKGROUND

In fuel generation systems, stable and repeatable performance for bothcontinuous and on/off operation are highly desirable. Stable fuelgeneration from fuel carriers relies on how well a uniform and constantreaction interface is maintained between a fuel carrier and liquidreactant. In conventional systems, this reaction control is achieved byutilizing a liquid fuel carrier and pumping a designated amount of thefuel carrier to catalysts. However, solution type fuel carriers are lessfavored due to their low energy density. While solid fuel carriers havehigher energy densities than liquid solutions, their further developmenthas been hampered by difficulty in achieving reliable reaction control.The reaction control of a solid fuel carrier system relies on both thepumping rate of liquid reactants and the size of a reaction interface.In practical cases, volatile hydrolysis reaction at the interface leavescavities or voids when the generated products flow away from theinterface. This results in a non-contact between a fuel surface andliquid delivery medium such as a nozzle or wick. When this occurs, theperformance of hydrogen generation system degrades over time.Furthermore, the performance of the fuel system becomes unpredictablewhen it is restarted after a stop period from the previous run.Typically, when the fuel system is investigated after its operation fora certain period, large gaps or voids are observed between thenon-reacted surface of the solid fuel and the liquid delivery mechanism(LDM) such as a nozzle, wick, or membrane. This lack of control inmaintaining constant and intact boundary between a solid fuel and liquiddelivery medium has been the largest obstacle to achieving reliableperformance of a solid fuel system.

Thus, there is a need in the fuel generator field to create a new anduseful reaction chamber. This invention provides such new and usefulreaction chamber.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic representation of a method of manufacturing areaction chamber.

FIGS. 2A, 2B, and 2C are schematic representations of a first, second,and third step, respectively, of a vacuum embodiment of the step ofstretching the body of the elastic enclosure to define a working lumen.

FIGS. 3A, 3B, and 3C are schematic representations of a first, second,and third step, respectively, of a first embodiment of the second stepof the vacuum embodiment.

FIG. 4 is a schematic representation of a second embodiment of thesecond step of the vacuum embodiment.

FIG. 5 is a schematic representation of a variation of the secondembodiment of the second step of the vacuum embodiment.

FIG. 6 is a schematic representation of a positive pressure embodimentof the step of stretching the body of the elastic enclosure to define aworking lumen.

FIG. 7 is a schematic representation of an embodiment of the step oforienting the fuel insert within the working lumen.

FIGS. 8A and 8B are schematic representations of a first and secondembodiment, respectively, of the step of inserting a liquid deliverymechanism into the reaction chamber.

FIG. 9 is a schematic representation of a first method of sealing theelastic enclosure opening about the liquid delivery mechanism.

FIG. 10 is a schematic representation of a first method of trimming aportion of elastic enclosure from the reaction chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments of the inventionis not intended to limit the invention to these preferred embodiments,but rather to enable any person skilled in the art to make and use thisinvention.

The method for manufacturing a reaction chamber comprises the steps ofstretching the body of an elastic enclosure to define a working lumenS200; orienting a fuel insert within the working lumen S300; and,restituting the elastic enclosure over the insert S400. This methodpreferably utilizes an elastic enclosure and a fuel insert. The methodpreferably produces a reaction chamber with the elastic enclosuredisposed substantially around the fuel insert, such that the elasticenclosure is in tension about the insert and applies a compressive forceto the insert. The reaction chamber is preferably used to contain andcontrol a fuel-generating reaction, more preferably ahydrogen-generating reaction. In operation, the elastic enclosuremaintains contact between a liquid reagent delivery mechanism and areaction zone, wherein the reaction zone is preferably the surface ofthe unreacted fuel insert. To address the issues described above, thereaction chamber of the preferred embodiments provides a moving boundaryinterface (i.e. the elastic enclosure) that ensures constant contactbetween a solid fuel insert and the liquid delivery mechanism and/or theliquid reagent by bringing the liquid delivery mechanism and/or theliquid reagent in contact with the varying contour of the reactingsurface of the fuel insert. When the fuel insert is consumed anddecreases in volume, the elastic enclosure shrinks and maintainssubstantially continuous contact with the insert surface. The assembledreaction chamber is preferably substantially similar to the reactionchamber disclosed in U.S. application Ser. No. 12/460,794, filed Jul.23, 2009, incorporated herein by this reference. However, the assembledreaction chamber may be any suitable elastic reaction chamber that mayfacilitate volume exchange with the reaction products and/or collector.The method is preferably automated and performed by machinery using oneor more machines, but may alternately be performed by hand, utilizingone or more assembly personnel.

The elastic enclosure 100 of the reaction chamber functions to apply acompressive force about substantially the whole of the fuel insert. Asshown in FIG. 1, the elastic enclosure preferably comprises asubstantially continuous body 140 that defines a lumen, and an openingportion 120 that defines the elastic enclosure opening. The elasticenclosure preferably takes little to no deformation set, restituting tothe original dimensions after long periods in a stretched position.Adequate restitution ability is desirable to allow substantiallycomplete consumption of the fuel insert; without adequate restitutionability, the elastic enclosure eventually loses continuous contact withthe fuel insert during operation, which may result in uncontrolled andincomplete reaction of the fuel insert. The elastic enclosure preferablyrestitutes completely to its original dimensions after stretching, butmay restitute to a size slightly larger or substantially larger than itsoriginal dimensions. In the end product, the elastic enclosurepreferably includes a first and a second outlet defining an LDM inletand a reaction product outlet, respectively, wherein the LDM inlet andreaction product outlet are preferably disposed near opposing ends ofthe fuel insert, but may alternatively be on the same end and be definedby the same elastic enclosure opening. The elastic enclosure ispreferably a formed membrane, more preferably a tube with a first and asecond opening. The tube diameter is preferably substantially constantthroughout the tube length, but may vary (e.g. one opening has a largerdiameter than the body, the body has a larger diameter that theopenings, etc.). The tube diameter is preferably smaller than thediameter and/or width of the fuel insert at any given point. The tubelength is preferably sized to encapsulate the entire length of theinsert, but may alternatively be longer or shorter than the insert. Thetube is preferably cut to length before assembly, but may alternately becut to length during assembly. The elastic enclosure may alternativelyhave any suitable shape or form. The elastic enclosure preferablycomprises material that is inert, but may comprise material that resistsdegradation and/or reaction with the fuel insert material, liquidreagent, and reaction products. The elastic enclosure is preferably madefrom silicone, latex, or any suitable elastomeric material, and may beadditionally reinforced (e.g. with a metal layer, other polymericmaterials, etc). In one preferred embodiment, the elastic enclosure ismade from platinum-cured silicone tubing such as SANI-TECH item numberSTHT-C-312-1F with a tensile strength of approximately 8.57 MPa and atensile modulus of approximately 2.13 MPa. The elastic enclosure ispreferably extruded, but may alternately be formed, injection molded,dipped, or made using any suitable manufacturing method.

The fuel insert 200 functions to store fuel and to provide a reactioninterface. This reaction interface is preferably along the surface ofthe fuel insert, and is preferably constantly changing as the insert isconsumed by the reaction. The fuel insert preferably forms fuel uponreaction with a liquid reagent, and preferably forms hydrogen gas butmay alternatively form any suitable fuel (e.g. methane, butane, etc.).The fuel insert preferably comprises a metal hydride fuel carrier, morepreferably sodium borohydride (SBH) fuel carrier, but may alternatelyinclude lithium borohydride, alane, or any other suitable fuel carrier.The fuel insert preferably comprises metal hydride powder compressedinto a solid insert (e.g. pill), but may alternately comprise a solidblock of metal hydride. The fuel insert may alternatively bemanufactured by injection molding, sintering, or any other suitablemethod of manufacturing a fuel insert. The fuel insert preferablyincludes guide grooves, preferably a liquid delivery mechanism (LDM)guide groove and/or an alignment groove. The LDM guide groove functionsto allow easy insertion and alignment of the LDM with the insert. Thealignment groove functions to align the fuel insert with other fuelinserts, the elastic enclosure and/or other components encapsulatedwithin the elastic enclosure in the end product (e.g. exhaust nozzles,filters, etc.). The guide grooves are preferably located on the exteriorof the fuel insert, but may alternately be located on the interior.However, the fuel insert may alternately include other grooves or notinclude any grooves at all. The fuel insert may additionally include anysuitable alignment features. The reaction chamber preferably includesone fuel insert, but may additionally include any number of fuel insertsof any composition.

The reaction chamber may additionally include a liquid deliverymechanism (LDM) 220 that functions to deliver a liquid reagent to thereaction zone. The reaction zone is preferably the surface of the fuelinsert, but may alternatively be on the interior of the fuel insert. TheLDM is preferably a flexible tube, but may alternatively comprise anozzle, multiple tubes of different lengths, multiple tubes of the samelength, multiple nozzles of different varieties, a combination of theabove, or any other suitable liquid delivery mechanism. The LDM ispreferably the longer than the length of the fuel insert such that itcovers the entirety of the fuel insert, but may alternately cover only aportion of the fuel insert, or be substantially shorter than the fuelinsert. However, the LDM may be any suitable configuration to deliverliquid reagent to the reaction zone. The LDM is preferably substantiallysolid such that it does not leak, but may alternatively have holes or beporous along a section (e.g. the section proximal to the insert afterassembly or the whole length). The LDM is preferably flexible, but maybe substantially rigid. The LDM is preferably impervious to the liquidreagent, and preferably comprises ultra-high molecular weightpolyethylene (UHMWPE), high-density polyethylene (HDPE), polypropylene,PTFE, PVDF, or any other suitable material. The LDM may additionallyinclude a distribution mechanism, such as wicking materials leading fromthe lumen of the LDM to the exterior to facilitate liquid reagentdistribution, pores along the fuel insert-contacting length, sidechannels, or any other suitable distribution mechanism. The reactionchamber preferably includes one LDM, but may alternatively include aplurality of LDMs of the same or of varying lengths.

The step of stretching the body of the elastic enclosure to define aworking lumen S200 functions to achieve an elastic enclosureconfiguration that allows for easy fuel insert insertion. The workinglumen 160 is preferably formed from the elastic enclosure body interior,wherein the elastic enclosure body is stretched to a diameter and lengththat readily accepts the desired portion of the fuel insert (e.g.stretched to achieve dimensions larger than the fuel insert, stretchedto a larger diameter than the insert, stretched to a longer length thanthe insert length or width, etc). S200 may additionally include the stepof halting and maintaining the working lumen configuration, wherein thestretching force is adjusted and/or maintained to retain the desiredworking lumen configuration.

In a first embodiment (“vacuum embodiment”) of S200, the working lumenis achieved by pulling suction on the exterior of the elastic enclosure,and preferably uses a vacuum tube 300 coupled to a vacuum generator(suction generator), wherein the vacuum tube includes an opening throughwhich the elastic enclosure is received into the vacuum tube lumen. Thevacuum tube is preferably substantially sealed except for the vacuumtube opening, and preferably has a substantially constant diameterthroughout its length but may alternately have a variable diameter. Asshown in FIG. 2, this embodiment preferably comprises the steps ofplacing the elastic enclosure body within the vacuum tube, wherein theelastic enclosure opening is left external the vacuum tube (S220);securing the elastic enclosure opening to the vacuum tube, whereinsecuring the elastic enclosure opening seals the vacuum tube openingabout the elastic enclosure body (S230); and pulling suction within thevacuum tube to expand the elastic enclosure body (S240). The step ofplacing the elastic enclosure body within the vacuum tube (S220) ispreferably accomplished by orienting the elastic enclosure body withinthe vacuum tube lumen, wherein the elastic enclosure opening is leftoutside the vacuum tube, as shown in FIG. 2A. The elastic enclosure ispreferably inserted into the vacuum tube from the top or the side, butthe vacuum tube may be inverted over the elastic enclosure. In thisstep, the elastic enclosure body is preferably sealed (i.e. the elasticenclosure opening is the only opening to the elastic enclosure lumen)prior to placement in the vacuum tube, but may alternately be sealedafter placement. The elastic enclosure body is preferably sealed by aknot, but may be sealed by clips, welding, adhering the opening edgestogether, or any other suitable method. This step is preferably usedwhen the elastic enclosure has more than one opening, for example, whenthe elastic enclosure is a tube. Alternatively, the elastic enclosuremay be manufactured to have only one opening, wherein the step ofelastic enclosure sealing is unnecessary. The vacuum tube lumen ispreferably lubricated prior to elastic enclosure placement, and ispreferably lubricated with a non-reactive powder (e.g. baby powder, cornstarch, talc, etc.), but may alternately be lubricated with a liquid.

As shown in FIG. 2B, the step of securing the elastic enclosure openingto the vacuum tube and sealing the vacuum tube opening about the elasticenclosure body S230 functions to seal the vacuum tube such that it canpull a vacuum, and to prevent the elastic enclosure from shifting whileit is being stretched to create the working lumen. This step S230preferably results in the opening portion of the elastic enclosure (e.g.the portion of the elastic enclosure near the opening) folded over thevacuum tube opening, with the elastic enclosure body enclosed within thevacuum tube lumen, and the elastic enclosure opening wrapped about thevacuum tube exterior. Step S230 may be accomplished using severaldifferent embodiments. Throughout these embodiments, the adhesiveproperties (e.g. tackiness) of the elastic enclosure material and theelasticity of the elastic enclosure (e.g. the restitution force)preferably secure the elastic enclosure position relative to the vacuumtube, but the elastic enclosure may be secured to the vacuum tube bymechanical means (e.g. clips, clamps, washers), by chemical means, or byany other suitable means. In a first embodiment of S230 (“tubestretching apparatus” embodiment), the elastic enclosure is pre-foldedS231 then transferred to the vacuum tube S233. In this embodiment, theelastic enclosure pre-folding occurs prior to the step of placing theelastic enclosure within a vacuum tube, and the step of transferring thefolded elastic enclosure seals and secures the elastic enclosure to thevacuum tube opening. As shown in FIG. 3, the step of pre-folding theelastic enclosure is preferably accomplished by folding the elasticenclosure opening over the radially contracted fingers of aenclosure-stretching apparatus S231 and radially stretching the foldedportion of the elastic enclosure incrementally until a working diameter(e.g. a diameter that can fit over the vacuum tube opening, preferably adiameter larger than the vacuum tube opening) is reached S232. As shownin FIG. 3A, the step of folding the elastic enclosure opening over thefingers of an enclosure-stretching apparatus S231 preferably includesthe sub-steps of installing the substantially unstretched elasticenclosure between the fingers of the enclosure-stretching apparatus,such that the fingers hold the body of the elastic enclosure and theopening portion (portion to be folded over the vacuum tube) is left freefrom the fingers (S231 a); and stretching the opening portion over thefingers, such that the fingers are disposed between the opening portionand the elastic enclosure body (S231 b). As shown in FIG. 3B, the stepof radially stretching the folded portion of the elastic enclosureincrementally to achieve a working diameter S232 is preferablyaccomplished by incrementally moving opposing pairs of fingers away fromeach other (e.g. by turning knobs or levers that control the radialposition of each finger), but may alternately be accomplished by movingany combination of the fingers away from each other to achieve asubstantially circular configuration. However, the step of pre-foldingthe elastic enclosure may be accomplished using any other suitablemethod. As shown in FIG. 3C, the step of transferring the folded elasticenclosure to the vacuum tube S233 preferably comprises the steps oforienting the vacuum tube opening within the fold (i.e. between theelastic enclosure body and opening portion) (S233 a), and advancing thevacuum tube towards the fold, pushing the folded elastic enclosure offthe enclosure-stretching apparatus and onto the vacuum tube opening(S233 b). S233 is preferably accomplished by placing the vacuum tubeunderneath the elastic enclosure within the tube stretching apparatus,such that the elastic enclosure body hangs down into the vacuum tubelumen, then pushing the vacuum tube up, into the fold, until the elasticenclosure is transferred onto the vacuum tube and is completely free ofthe tube stretching apparatus. Alternatively, the step of transferringthe folded elastic enclosure to the vacuum tube S233 may include thesteps of placing the vacuum tube opening inside the elastic enclosurelumen (such that the vacuum tube is inverted), sliding the elasticenclosure opening portion off the tube stretching apparatus fingers ontothe vacuum tube, and inverting the elastic enclosure body into thevacuum tube lumen. However, the folded elastic enclosure may betransferred onto the vacuum tube in any suitable orientation (e.g.sideways, etc) utilizing any suitable method. The first embodiment ofS230 may additionally include the sub-step of pre-stretching the elasticenclosure prior to installation in the tube stretching apparatus,wherein pre-stretching conditions the elastic enclosure to a desiredelasticity. Pre-stretching the elastic enclosure preferably includespressurizing the elastic enclosure such that the elastic enclosureopening undergoes a slight plastic deformation to allow for easierfolding over the fingers, but may alternately utilize any suitablepre-stretching method. In a second embodiment of S230 (“flared opening”embodiment), as shown in FIG. 4, the elastic enclosure has a flaredopening that is created and/or folded over the vacuum tube opening. Theflared opening is preferably the opening portion of the elasticenclosure (to be folded over the vacuum tube), and preferably flares toa larger diameter from the elastic enclosure body, wherein the largerdiameter is preferably the working diameter (e.g. substantially close toor larger than the vacuum tube diameter), such that minimal additionalstretching is required to fold the flared opening over the vacuum tubeopening. As shown in FIG. 5, the elastic enclosure may be manufacturedwith an opening smaller than the working diameter, wherein a flaredopening is created. The flared opening is preferably created by placingthe sealed elastic enclosure body within the vacuum tube lumen, whileleaving the opening portion outside the vacuum tube S210; coupling theelastic enclosure opening to a positive pressure source (e.g. compressedair, compressed air generator, etc.) S235; pressurizing the elasticenclosure such that a flare with a larger diameter than the vacuum tubeopening is created in the opening portion S236; and temporarily sealingoff the elastic enclosure opening when a working diameter is reached tomaintain internal pressure (e.g. by pinching, clamping, etc.) S236 a.Elastic enclosure securing and sealing of to the vacuum tube openingS230 is then accomplished by sliding the flared opening over the vacuumtube exterior while slowly releasing the internal pressure. Any excesselastic enclosure near the vacuum tube opening may be trimmed off(without perforating the body of the elastic enclosure), and theremaining elastic enclosure may be rolled over the vacuum tube exterior.However, any suitable method of creating a flared opening may be used.

As shown in FIG. 2C, the step of reducing pressure within the vacuumtube to expand the elastic enclosure body S240 functions to stretch thebody of the elastic enclosure to define the desired working lumen. Sincethe elastic enclosure body is sealed within the vacuum tube lumen (bythe seal formed by folding the opening portion over the vacuum tubeopening edge), a suction within the vacuum tube lumen stretches theelastic enclosure body to define the working lumen because the exteriorof the elastic enclosure body (within the vacuum tube lumen) experiencesa lower pressure than the interior of the elastic enclosure body. S240is preferably accomplished by coupling the vacuum tube lumen to a vacuumpump (e.g. suction generator) and removing a portion of the air from thevacuum tube (e.g. pulling a vacuum), but may alternately be accomplishedby rapidly cooling the vacuum tube lumen, or by any suitable manner thatreduces pressure within the vacuum tube lumen.

In a second embodiment of S200, the working lumen is created byutilizing positive pressure within the elastic enclosure body (“positivepressure embodiment”). In a first embodiment of the positive pressureembodiment (“enclosure-stretching apparatus lumen stretching”embodiment), as shown in FIG. 6, the fingers of a tube-stretchingapparatus are inserted into the lumen of the elastic enclosure S237 aand incrementally radially expanded to achieve the desired working lumenS237 b. The fingers are preferably inserted in the lumen to a depthsubstantially equal to the desired length of the working lumen, and thefingers are preferably expanded to form a substantially circular workinglumen cross section of the working diameter, but may alternatively beexpanded to form an ovular lumen cross section, a bean-shaped lumencross section, or any suitable cross section. In this embodiment, thefingers of the enclosure-stretching apparatus are preferably strongenough to withstand deformation from the restitution force of theelastic enclosure. In a second embodiment of the positive pressureembodiment, the interior of the elastic enclosure is preferablypressurized and expanded to form the working lumen. This is preferablyaccomplished by fluidly coupling the elastic enclosure opening to apressurized fluid source (e.g. by placing the elastic enclosure openingover the source's fluid nozzle and securing a washer over thearrangement), wherein the pressurized fluid source is preferablycompressed fluid that comprises compressed air (e.g. from a canister orfrom an air compressor), but may alternately comprise compressed liquidor any suitable fluid. The positive pressure is then preferablymaintained throughout the step of orienting the fuel insert within theworking lumen S300.

The step of orienting the fuel insert within the working lumen S300functions to ensure that the elastic enclosure restitutes over theinsert in a desired configuration (shown in FIG. 1). Furthermore, S300may additionally ensure that other components placed within the workinglumen are aligned properly relative to each other. As shown in FIG. 7,S300 preferably includes the steps of maintaining the working lumenS310; positioning the fuel insert relative to the working lumen openingS320; and inserting a portion of the fuel insert into the working lumenS330. The step of maintaining the working lumen S310 functions to keepthe working lumen in the desired configuration, and is preferablyaccomplished by maintaining the stretching force on the elasticenclosure body (e.g. by maintaining the vacuum in the vacuum tubelumen). The step of positioning the fuel insert S320 preferably readiesthe assembly for fuel insert insertion into the working lumen. This ispreferably accomplished by approximately aligning the longitudinal axesof the fuel insert and the working lumen, but may alternately beaccomplished in any suitable manner for any desired orientation. Thestep of positioning the fuel insert S320 may additionally include thestep of positioning additional components relative to the fuel insert.For example, the reaction chamber may include an exhaust nozzle thatfacilitates reaction product flow out of the reaction chamber, whereinthe exhaust nozzle is coupled to the fuel insert within the elasticenclosure. In this example, the exhaust nozzle is placed on one end ofthe fuel insert (preferably on top, wherein the fuel insert is standingon its end). The step of positioning the fuel insert S320 mayadditionally utilize a guide 210, wherein the guide may be disposed onthe interior of the working lumen and extracted later, be disposed onthe fuel insert, or be disposed on the exterior of the elasticenclosure. The guide preferably has or creates geometry that orients thefuel insert in the desired orientation, wherein the fuel insert hascomplimentary geometry to the guide. The guide may additionally coupleor align multiple components in a desired configuration. For example, ifmultiple fuel inserts are to be inserted into the elastic enclosure, theguide may be used along a side of the inserts to ensure relativeposition retention. The guide is preferably an alignment rod, but mayalternatively be alignment patterns, guide rails, a clip, or any othersuitable guide. The guide is preferably formed as an integral piece ofthe fuel insert or as an integral piece of the elastic enclosure, butmay alternatively be a separate piece that couples to the elasticenclosure and/or fuel insert, wherein the separate guide is removedafter fuel insert insertion into the working lumen or after elasticenclosure restitution. The step of positioning the fuel insert S320preferably includes the steps of orienting the fuel insert on end andinverting the working lumen over the fuel insert. However, the fuelinsert may be positioned over the working lumen, wherein the workinglumen opening faces upward, or be positioned to the side of the workinglumen, wherein the working lumen opening faces the fuel insert. The stepof inserting a portion of the fuel insert into the working lumen S330functions to control the longitudinal coverage of the elastic enclosureover the fuel insert. The step of inserting a portion of the fuel insertinto the working lumen S330 preferably includes advancing the fuelinsert into the working lumen; and halting advancement when the desireddepth is reached. The fuel insert may be advanced by moving the fuelinsert into the working lumen, by moving the working lumen over the fuelinsert, or by advancing both the fuel insert and the working lumentoward each other. The fuel insert is preferably advanced along oneaxis, wherein the other axes are held constant (e.g. no rotation), butmay alternatively rotate as it is inserted into the working lumen. Thefuel insert orientation relative to the working lumen opening ispreferably fixed in all axes of rotation and translation except for theaxis of insertion. Fuel insert insertion is preferably halted at a depthsubstantially near the desired longitudinal coverage distance, whereinthe portion of the fuel insert to be encapsulated by the elasticenclosure is preferably inserted until the uninserted portion of thefuel insert has a length substantially equal to the combined length ofthe desired fuel insert external section and the opening portion of theelastic enclosure, wherein the opening portion of the elastic enclosureis unrolled/unfolded to cover the fuel insert after restitution.However, the fuel insert may alternatively be inserted any desireddistance. For example, if the fuel insert is desired to be entirelyencapsulated by the elastic enclosure (e.g. the desired longitudinalcoverage distance is the entire length of the fuel insert), then thefuel insert is entirely inserted into the working lumen, and may bedropped in, pushed in, guided in, or any suitable manner of placing theentire fuel insert into the working lumen.

The step of restituting the elastic enclosure over the fuel insert S400functions to create continuous contact between the elastic enclosure andthe fuel insert, (shown in FIG. 1). S400 is preferably achieved byreleasing the stretching force on the elastic enclosure body, andrelying on the elasticity of the elastic enclosure to achieverestitution about the fuel insert. In the vacuum embodiment, S400preferably includes the step of releasing the suction in the vacuumtube. In the positive pressure embodiment, S400 preferably includesremoving the pressure generation mechanism (e.g. contracting togetherand/or removing the enclosure-stretching apparatus fingers, releasingthe pressure within the elastic enclosure interior). However, this stepmay alternatively heat the elastic enclosure such that it shrinks aboutthe fuel insert, cinch the elastic enclosure about the fuel insert withelastic bands, pull a vacuum on the fuel insert-elastic enclosureassembly, or utilize any other suitable method of restituting theelastic enclosure over the fuel insert. S400 may additionally includethe step of retaining the fuel insert position during restitution, whichfunctions to achieve the desired fuel insert-elastic enclosurepositioning after restitution. Because the elastic enclosure iscompressing over the fuel insert during restitution, the insertedorientation (insertion distance, relative positioning of components,etc) may change. This step is preferably accomplished by holding thefuel insert in the desired position relative to the working lumenopening and possibly adjusting (e.g. pushing and/or pulling) the fuelinsert position relative to the working lumen opening. S400 mayadditionally include the step of unsealing the elastic enclosureopenings, wherein the elastic enclosure opening seals are removed (e.g.cut off, unclipped, untied, etc.).

As shown in FIG. 8, the method of manufacturing a reaction chamber mayadditionally include the step of inserting a liquid delivery mechanismS500, which functions to create a fluid pathway between the exterior ofthe reaction chamber and the reaction zone within the reaction chamberthrough which liquid reagent can flow. The outlet end (reaction end) ofLDM is preferably inserted into the elastic enclosure through theelastic enclosure opening, and is preferably inserted along the fuelinsert length such that the outlet end is substantially near the fuelinsert end distal the elastic enclosure opening (i.e. the LDM isinserted such that it encompasses substantially the entire length of thefuel insert). However, the LDM may be inserted through any other openinginto the elastic enclosure. The LDM may alternatively/additionally beinserted such that it encompasses only a portion of the fuel insert(e.g. three-quarters, half, one-third, etc. of the fuel insert length),inserted from the side, or inserted in any suitable configuration. TheLDM is preferably inserted between the elastic enclosure and the fuelinsert, more preferably within a groove or channel in the fuel insert(wherein the groove may also function as the guide groove), but mayalternatively/additionally be inserted into the fuel insert. If aportion of the fuel insert is left outside the elastic enclosure, theLDM is preferably inserted from the end with the uncovered fuel insert.In a first embodiment of S500, the LDM is inserted after restitution ofthe elastic enclosure (S400). As shown in FIG. 8A, the first embodimentof step S500 preferably includes the steps of lifting the elasticenclosure away from the fuel insert S522; orienting the LDM S524; andinserting the LDM into the reaction chamber S526. Lifting the elasticenclosure away from the fuel insert S522 functions to create a space forLDM insertion, and is preferably performed where the LDM is desired tobe inserted. S522 is preferably performed by inserting a liftingmechanism (e.g. a spatula, shim, rod, etc.) between the elasticenclosure and the fuel insert at the desired position and prying theelastic enclosure away from the fuel insert. However, any suitablemethod of creating an insertion space for the LDM may be utilized.Orienting the LDM S524 functions to insert the LDM in the correctconfiguration relative to the reaction chamber. The LDM is preferablyoriented such that the outlet is inserted into the reaction chamberfirst, but may be oriented in any suitable configuration. Inserting theLDM into the reaction chamber S526 functions to achieve the desired LDMdepth, placing the LDM outlet(s) in the desired position(s) relative tothe fuel insert. The LDM is preferably pushed in through the insertionspace, but may alternatively be guided in, wherein a guide (e.g. fishingwire) is initially threaded through the desired LDM pathway and the LDMis threaded over the guide. The LDM may alternatively be inserted usingany other suitable method. In a second embodiment of step S500, as shownin FIG. 8B, the LDM is inserted before restitution of the elasticenclosure over the fuel insert (S400). In this embodiment, the LDM isoriented to the desired configuration and position, inserted between theelastic enclosure and the fuel insert, and retained in its positionrelative to the fuel insert until elastic enclosure restitution.

As shown in FIG. 9, the method of manufacturing a reaction chamber mayadditionally include sealing the elastic enclosure opening about the LDMS600. This step functions to establish and maintain a fluid seal aboutthe fuel insert and reaction zone, such that reagents and reactionproducts do not leak out from the LDM end, and to retain the LDMposition. This step is preferably used when the LDM inlet of the elasticenclosure is a separate opening from the reaction product outlet, butmay be used when the LDM inlet uses the same elastic enclosure openingas the reaction product outlet. Shoo preferably accomplished by allowingrestitution of the elastic enclosure about the LDM, compressing the LDMagainst the fuel insert, but may be accomplished by cinching andtightening the elastic enclosure opening over the LDM with a cintureplaced over the elastic enclosure substantially near the elasticenclosure opening, by heating and shrinking the elastic enclosure aboutthe LDM, by melting the elastic enclosure to the LDM, by applying asealant to the gap between the LDM and elastic enclosure, or by anyother suitable sealing method.

As shown in FIG. 10, the method of manufacturing a reaction chamber mayadditionally include the step of trimming a portion of elastic enclosurefrom the reaction chamber S700. This step functions to control the sizeof the reaction chamber, to ensure adequate fuel insert retention withinthe elastic enclosure, and to achieve an adequate reaction productoutlet. Excess elastic enclosure (e.g. elastic enclosure not contactingthe fuel insert and/or LDM) is preferably trimmed off after restitutionof the elastic enclosure over the insert, and may be repeated after LDMinsertion or after sealing the elastic enclosure opening about the LDM.However, the elastic enclosure may be trimmed (e.g. cut) to widenexisting openings (e.g. widen the opening about the exhaust nozzle, ifused), or to create additional openings, for example reaction productoutlet(s), in desired positions along the elastic enclosure. This stepis preferably performed with a razor, but may alternately be performedby laser cutting, shearing, or any other suitable trimming method.

The method of manufacturing a reaction chamber may additionally includerepeating any of the aforementioned steps, preferably at least S200,S300, and S400, for additional elastic enclosures, such that the fuelinsert is encapsulated by two or more elastic enclosures.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

1. A method for manufacturing a reaction chamber, the reaction chamberhaving a fuel insert and an elastic enclosure, the elastic enclosurehaving a body and an opening portion that defines an opening in theelastic enclosure, the method comprising the steps of: a) stretching thebody of the elastic enclosure to define a working lumen; b) orientingthe fuel insert within the working lumen; and c) restituting the elasticenclosure over the insert.
 2. The method of claim 1, wherein step (a)further includes the steps of: placing the body of the elastic enclosurewithin a vacuum tube, wherein the opening of the elastic enclosure isdisposed outside the vacuum tube; securing the elastic enclosure openingportion to the vacuum tube opening, thereby sealing the vacuum tubeopening; and defining a working lumen in the elastic enclosure bypulling a suction within the vacuum tube to expand the elastic enclosurebody.
 3. The method of claim 2, wherein step (a) further includes thestep of sealing the elastic enclosure to leave one opening.
 4. Themethod of claim 3, wherein the elastic enclosure is a tube, and the endopposing the opening is sealed.
 5. The method of claim 2, wherein step(c) includes the step of releasing the suction within the vacuum tube.6. The method of claim 2, wherein the step of securing the elasticenclosure opening portion to the vacuum tube opening includes disposingthe elastic enclosure opening portion in a fold over the vacuum tubeopening, such that the body of the elastic enclosure is encapsulatedwithin the vacuum tube lumen and the elastic enclosure opening portionis disposed outside the vacuum tube.
 7. The method of claim 6, whereindisposing the elastic enclosure opening portion in a fold over thevacuum tube opening comprises the steps of: folding the elasticenclosure opening portion over a stretching apparatus; stretching theelastic enclosure opening portion radially to a diameter larger than thevacuum tube diameter; sliding the vacuum tube into the fold between theelastic enclosure opening portion and the elastic enclosure body; andtransferring the folded elastic enclosure to the vacuum tube.
 8. Themethod of claim 6, wherein the elastic enclosure opening portion hassubstantially the same diameter as the body.
 9. The method of claim 6,wherein the elastic enclosure is stretched prior to disposing theelastic enclosure opening portion in a fold over the vacuum tubeopening.
 10. The method of claim 6, wherein the elastic enclosureopening portion is flared outward from the body.
 11. The method of claim10, wherein a portion of the flared opening has a diameter larger thanthe vacuum tube diameter.
 12. The method of claim 10, wherein the methodfurther includes the step of flaring the elastic enclosure openingportion, which includes the steps of: placing a portion of the elasticenclosure body within the vacuum tube lumen while leaving a secondportion of the elastic enclosure outside the vacuum tube, wherein thesecond portion is proximal to the elastic enclosure opening portion;coupling the elastic enclosure opening to a pressure source; andpressurizing the elastic enclosure such that a section of the secondportion is flared to a diameter larger than the vacuum tube diameter.13. The method of claim 12, wherein the step of disposing the elasticenclosure opening portion in a fold over the vacuum tube openingincludes the step of pushing the flared portion of the elastic enclosureover the exterior of the vacuum tube.
 14. The method of claim 2, whereinstep (a) further includes the step of lubricating the vacuum tube. 15.The method of claim 1, wherein step (b) further includes the steps of:positioning the fuel insert relative to the working lumen opening; andinserting a portion of the fuel insert into the working lumen.
 16. Themethod of claim 15, wherein the step of positioning the fuel insertincludes using a guide.
 17. The method of claim 16, wherein the fuelinsert includes multiple pieces, and the guide retains the relativepositions of the multiple pieces.
 18. The method of claim 15, whereinthe fuel insert is fully inserted into the working lumen.
 19. The methodof claim 15, wherein the step of inserting a portion of the fuel insertinto the working lumen includes the step of inverting the working lumenover the fuel insert.
 20. The method of claim 1, wherein step (c)includes the step of maintaining the fuel insert position within theworking lumen.
 21. The method of claim 1, further comprising the step ofinserting a liquid delivery mechanism between the fuel insert and theelastic enclosure.
 22. The method of claim 21, wherein the step ofinserting a liquid delivery mechanism occurs before the step ofrestituting the elastic enclosure over the fuel insert, wherein the stepof inserting a liquid delivery mechanism includes the steps of:positioning the liquid delivery mechanism within the working lumen; andmaintaining the liquid delivery mechanism position during restitution.23. The method of claim 21, wherein the step of inserting a nozzleoccurs after the step of restituting the elastic enclosure over theinsert, wherein the step of inserting a liquid delivery mechanismincludes the steps of: stretching a portion of the elastic enclosureaway from the insert; positioning the liquid delivery mechanism betweenthe insert and the elastic enclosure; and releasing the portion of theelastic enclosure.
 24. The method of claim 1, further comprising thestep of trimming the excess restituted elastic enclosure from thereaction chamber.
 25. The method of claim 1, wherein steps (a), (b) and(c) are repeated for a second elastic enclosure, wherein the fuel insertis encapsulated in a first elastic enclosure.
 26. A method formanufacturing a reaction chamber, the reaction chamber comprising ametal hydride insert and an elastic enclosure, the elastic enclosureincluding a body and an opening portion that defines an opening in theelastic enclosure, the method comprising: placing the body of theelastic enclosure within a vacuum tube, wherein the opening portion ofthe elastic enclosure is disposed outside the vacuum tube; securing theelastic enclosure opening portion to the vacuum tube opening, therebysealing the vacuum tube opening; defining a working lumen in the elasticenclosure by reducing air pressure within the vacuum tube to expand theelastic enclosure body; maintaining constant vacuum tube pressure whenthe elastic enclosure is stretched to a desired working lumen size;orienting the metal hydride insert within the working lumen; maintainingthe insert orientation; and allowing pressure increase within the vacuumtube to allow restitution of the elastic enclosure about the insert. 27.The method of claim 26, further comprising the step of inserting aliquid delivery mechanism between the insert and the elastic enclosure.28. The method of claim 26, wherein the step of securing the elasticenclosure opening to the vacuum tube opening includes disposing theelastic enclosure opening in a fold over the vacuum tube opening edge,such that the body of the elastic enclosure is enclosed within thevacuum tube lumen and the elastic enclosure opening is disposed on thevacuum tube exterior.
 29. The method of claim 28, wherein the step ofdisposing the elastic enclosure opening in a fold over the vacuum tubeopening includes the steps of: folding the elastic enclosure openingportion over a stretching apparatus; stretching the elastic enclosureopening portion radially to a diameter larger than the vacuum tubeopening diameter; sliding the vacuum tube into the fold between theelastic enclosure opening portion and the elastic enclosure body; andtransferring the folded elastic enclosure to the vacuum tube.
 30. Themethod of claim 28, wherein the elastic enclosure opening portion isflared outward from the body, and the step of disposing the elasticenclosure opening in a fold over the vacuum tube opening includes thestep of stretching the flared opening over the vacuum tube opening. 31.The method of claim 30, further comprising the step of flaring theopening, which includes the steps of: placing a portion of the elasticenclosure body within the vacuum tube lumen while leaving a secondportion of the elastic enclosure outside the vacuum tube, wherein thesecond portion includes the elastic enclosure opening portion; couplingthe elastic enclosure opening to a pressure source; and pressurizing theelastic enclosure such that the second portion of the elastic enclosureis flared to a diameter larger than the vacuum tube diameter; whereinthe step of disposing the elastic enclosure opening in a fold over thevacuum tube opening includes the step of pushing the flared portion ofthe elastic enclosure over the exterior of the vacuum tube.